Properties of Soymilk Prepared from Soybeans of Different Varieties

Abstract

The properties of soymilk, which prepared from soybeans of six varieties having different subunit composition, were studied. Soymilk's protein particles were fractionated in size by differential centrifugation. The particles of more than 100 nm, 100–40 nm, and less than 40 nm in diameter were obtained as large protein particles (LP), medium protein particles (MP), and supernatant protein (SP), respectively. The LP content in all raw soymilks decreased and the MP content increased by heating, but the MP content in soymilk prepared from GILM (7 S rich) did not increase so much by heating. When calcium chloride was added to the soymilks, the protein solubilities of the soymilk from Karikei 434 (11 S rich) decreased sharply between 6 and 8 mM calcium chloride, while that from GILM decreased sharply between 10 and 12 mM. The concentration of magnesium chloride, which began to decrease the protein solubilities, was similar to that of calcium chloride. But a decreasing slope of the protein solubilities by magnesium chloride was gentler than that by calcium chloride. The precipitation pH of protein by magnesium chloride was 0.1 pH higher than that by calcium chloride. Phytate in the soymilks accelerated a pH-decrease on the addition of calcium chloride. These results suggest that higher calcium and magnesium concentrations are required for the 7 S globulin rich-soymilk coagulation than for normal soymilk coagulation, and that the pH decrease by the addition of calcium in phytate rich-soymilk is greater than that in low phytate soymilk. © 1995, Japanese Society for Food Science and Technology. All rights reserved.